Externalizing (EXT) psychopathology (Krueger et al., 2002) encompasses various domains of commonly co- occurring psychiatric disorders, including attention deficit/hyperactivity disorder, childhood oppositional defiance/conduct disorder, and adult criminal deviance;it also reflects a constellation of disinhibited personality traits related to antisociality/unconventionality, affect/emotion dysregulation, and impulsivity/poor behavioral constraint (Bogg &Finn, 2009;Gorenstein &Newman, 1980;Krueger, 2002). Although the individual and societal costs of EXT psychopathology are well known, much remains unknown with regard to which cognitive and motivational processes are etiologic mechanisms in EXT psychopathology. Ideally, a full understanding of the causal mechanisms in EXT psychopathology would lead to more empirically-informed ways to diagnose, predict, and ameliorate this significant and wide reaching source of human suffering. Towards this end, recent empirical research suggest reduced attentional control and short-term activation in working memory (WM) are intermediate mechanisms in the neglect of future consequences, preference for immediate gratification, and poor passive avoidance tendencies associated with persistent EXT psychopathology (Finn, 2002;Endres et al., under review). Moreover, recent clinical findings suggest attention and WM training paradigms are viable interventions for early onset EXT psychopathology (e.g., Klingberg et al., 2002). The proposed study builds on this work by developing mathematically rigorous experimental and analytical tools for determining the role that reduced WM maintenance capacity and retrieval efficiency (i.e., "how much" and "how fast" information can be used to reliably guide behavior) plays in the maladaptive approach-avoidance tendencies (i.e., hypersensitivity to reward and hyposensitivity to punishment) associated with early onset and persistent EXT psychopathology. The proposed study will add to existing theoretical, empirical, and clinical research via three specific aims. The first is by using System Factorial Technology (Townsend &Nozawa, 1995) as a mathematical framework for modeling the association between EXT psychopathology and reduced controlled attention and short-term activation processes in WM. The second is by using Decision Field Theory (Townsend &Busemeyer, 1993, 1992) as a mathematical framework for modeling the effects of cognitive load on the association between EXT psychopathology and difficulty discriminating approach-avoidance signals, modulating approach-avoidance responses, and deliberating over approach-avoidance decisions. The third is by using structural equations modeling to determine whether the effects of cognitive load on the association between EXT psychopathology and approach-avoidance tendencies are mediated by controlled attention and short-term activation processes in WM. Overall, the proposed study represents an important step in a program of research aimed at elucidating and intervening on the intermediate neurocognive and neuroaffective mechanisms that underlie a persons'unique constitutional and environmental risk for an early onset and persistent course of EXT psychopathology. PUBLIC HEALTH RELEVANCE: In line with NIMH's strategic object 1.4, the proposed study attempts to develop, validate, and disseminate more mathematically rigorous methodologies for assessing those cognitive and motivational mechanisms that are putative markers of etiologic vulnerability to externalizing psychopathology. Because laboratory tasks will be needed in future investigations into which brain-behavior systems support both vulnerability to and protection against the onset and persistence of externalizing psychopathology, mathematical models of performance on these task will be an important means to link dimensional models of EXT psychopathology together with neuroscience methods. In this way, the technologies developed and tested in the PS could eventually lead to more individualized and empirically-informed ways to diagnose, predict, and ameliorate mental illness, in general, and externalizing psychopathology, in particular.